Conventionally, for example, a cellular system has been known as one of communication systems using a mobile communication terminal such as a car cellular phone or a mobile cellular phone.
FIG. 4 is a diagram for explaining a relationship among cells (service areas) and base stations in such a cellular system.
Namely, as shown in FIG. 4, for example, in a communication system using a mobile communication terminal such as a car cellular phone or a mobile cellular phone, a position of the mobile communication terminal 1 is registered as a cellular system in the corresponding to base stations 11, 12, 13, 14, . . . when the mobile communication terminal comes into one of cells 21, 22, 23, 24, . . . which are service areas called cells, respectively, so that respective base stations 11, 12, 13, 14, . . . enable the mobile communication terminal 1 to carry out communication with a desired opposite party.
For example, as shown by broken line arrow A in FIG. 4, when the mobile communication terminal moves from the cell 21 to the cell 22, communication services can be received from the double base stations 11 and 12 of the cell 21 and the cell 22. In this case, the mobile communication terminal can use an incoming radio wave whose power is stronger from the cell 21 or the cell 22 of one of the base station 11 and the base station 12, or incoming radio waves from the both of the cell 21 and the cell 22.
In this case, when the mobile communication terminal moves from the cell 21 to the cell 22 as shown by the above-described arrow A, the mobile communication terminal automatically switches the connection state from the base station 11 to the base station 12 (hereinafter, called “a transition of the connection state”).
Accordingly, at a manufacturer of mobile communication terminals, it is necessary to execute a connection transition test for testing whether or not a transition of the connection state is correctly executed in the mobile communication terminal, in advance, before shipping the mobile communication terminal.
In such a connection transition test, a method is used in which the position thereof is fixed without moving the mobile communication terminal itself, a plurality of test signals corresponding to the cells 21, 22, 23, 24, . . . are successively generated at the test system side, and simulated communication with the mobile communication terminal is made by means of a protocol in accordance with the communication system, thereby testing a transition of the connection state of the mobile communication terminal.
Namely, a system simulator is configured on the test system side, and the system simulator makes communication with the mobile communication terminal, thereby carrying out a connection transition test with respect to the mobile communication terminal.
As a method for testing a mobile communication terminal in such a communication system, for example, there is a radio resource management (RRM) test in accordance with the regulations described in non-Patent document 1 (3GPP TS 34. 121, V5. 4. 0, June 2004, 3GPP Organizational Partners [ARIB, ATIS, CCSA, ETSI, TTA, TTC], France, Contents No. 34-148, 184-212 [pp1-63]). To put it simply, this RRM test is to carry out a connection test with a base station or a procedure test with respect to a mobile communication terminal.
RRM tests include a test relating to a detecting time of a random access channel (RACH).
Note that as a RACH receiver for receiving a preamble part and a message part on the RACH, or the like, a receiver disclosed in Patent document 1 (Jpn. Pat. Appln. KOKAI Publication No. 2002-217866) has been known. Then, the above-described test relating to a detecting time of a RACH is, in short, carried out as follows.
Namely, in FIG. 4, when the mobile communication terminal transmits a request (preamble part) to the base station 12 in order for the mobile communication terminal to make a transition of the receiving state from a state of receiving the cell 21 to the cell 22, the base station 12 responds to this request while raising transmitting power in the cell 22.
Then, the base station 12 transmits a response signal, and thereafter, waits for a response (message part) from the mobile communication terminal at a predetermined timing.
Accordingly, the above test relating to a detecting time of a RACH is carried out by examining whether or not a time in which the response (message part) from the mobile communication terminal is detected at a predetermined timing is within a predetermined detecting time.
FIG. 5 is a functional block diagram showing a configuration of a conventional test system for carrying out the RRM test and the test relating to a detecting time of a RACH therein.
In FIG. 5, a transmission/reception unit 3 has functions of respective transmitters/receivers 3a, 3b, 3c, 3d, . . . which correspond to the cells 21, 22, 23, 24, . . . in FIG. 4.
Further, the functions of the respective transmitters/receivers 3a, 3b, 3c, 3d, . . . naturally include a function of making communication connection by exchanging messages necessary for a predetermined protocol with a mobile communication terminal (user equipment [UE]) 1 in the same way as in the base stations 11, 12, 13, 14, . . . in FIG. 4.
The transmission/reception unit 3 transmits predetermined test signals to the mobile communication terminal (UE) 1 via a connection unit 2 by the functions of the respective transmitters/receivers 3a, 3b, 3c, 3d, . . . , and receives a response signal transmitted from the mobile communication terminal (UE) 1.
The reception measurement unit 4 has a function of carrying out a test for confirming a transition of the connection state of the mobile communication terminal (UE) 1 by analyzing and measuring a response signal transmitted from the mobile communication terminal (UE) 1 due to the communication connection between the transmission/reception unit 3 and the mobile communication terminal (UE) 1.
Note that the transmission/reception unit 3 and the reception measurement unit 4 are configured to operate synchronously.
Further, the reception measurement unit 4 has a function of time measurement or the like.
Then, because the mobile communication terminal (UE) 1 carries out transmission and reception by a radio propagation signal with the transmission/reception unit 3, the reception measurement unit 4 is configured so as to have incorporated therein a spectrum analyzer or the like which can measure the spectrum, the band, power, and the like thereof in order to test the characteristic of the propagation signal at a radio frequency domain.
The time measurement at the reception measurement unit 4 is carried out by receiving a response signal from the mobile communication terminal (UE) 1 in response to the test signal from the transmission/reception unit 3 at the reception measurement unit 4, and by detecting the reception time and measuring the time.
For example, the reception measurement unit 4 converts a frequency of a received signal from the mobile communication terminal (UE) 1 with respect to a test signal from the transmission/reception unit 3, into an intermediate frequency by the built-in spectrum analyzer, and sweeps time at the intermediate frequency. In this manner, the reception measurement unit 4 carries out measurement due to a time domain in the same way as an oscilloscope, thereby measuring time.
As described above, the transmission/reception unit 3 and the reception measurement unit 4 have both of the system simulator function and the measurement function (test function).
In the following description, the transmission/reception unit 3 and the reception measurement unit 4 may be collectively called a system simulator in some cases.
Note that the connection unit 2 may connect the mobile communication terminal (UE) 1 and the system simulator (the transmission/reception unit 3 and the reception measurement unit 4) interactively with a cable, or may connect them via an antenna.
A test procedure control unit 5 has a time setting unit 5a, and controls the system simulator (the transmission/reception unit 3 and the reception measurement unit 4) by outputting control information including time setting information in accordance with the regulation of the connection test in the above-described communication system, for example, a procedure by which the RRM test of W-CDMA and the test relating to a detecting time of a RACH therein as described above are carried out.
In particular, in the communication system as described above, there is regulated in the regulation described above that, when the mobile communication terminal (UE) 1 moves among the cells 21, 22, 23, 24, . . . , the mobile communication terminal (UE) 1 makes a transition so as to receive with a predetermined quality by completing reception switching and registration within a predetermined time passage. Therefore, the mobile communication terminal (UE) 1 must satisfy these sequential operations.
Accordingly, the test procedure control unit 5 has a predetermined test procedure for testing whether or not the sequential operations in accordance with the regulation as described above are satisfied with respect to the mobile communication terminal (UE) 1 via the system simulator (the transmission/reception unit 3 and the reception measurement unit 4).
When the system simulator (the transmission/reception unit 3 and the reception measurement unit 4) is operating as set at the time setting unit 5a of the test procedure control unit 5, a determining unit 6 determines whether or not the transition of the connection state among the cells 21, 22, 23, 24, and . . . , in the mobile communication terminal (UE) 1 is carried out within a predetermined time.
This determining unit 6 appropriately processes and determines the result of the above-described determination, and outputs the final test result as numeric data to a display unit 7 or the like.
In the test system for the mobile communication terminal according to the prior art, a display on the display unit 7 depends on the numeric display by only numeric data in accordance with each measurement item.
Then, in the prior art, the display on the display unit 7 is carried out so as to individually display numeric data of time measurement in accordance with each measurement item, determined results, or time waveform display.
Accordingly, in the prior art, there is the problem that, when the mobile communication terminal (UE) 1 responds abnormally at a time different from a normal time, or when there is abnormality in numeric data, it is hard for an operator to grasp a timing relationship between exchanging messages and signal waveforms between the mobile communication terminal (UE) (1) and the transmission/reception unit 3 so as to be visually recognizable.